EAL

GDM: Postpartum Care (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To define the recurrence rate of gestational diabetes mellitus in a subsequent pregnancy and to determine what factors could be predictive.

Inclusion Criteria:

GDM, based on 75-g OGTT at beginning of the 3^rd trimester: 2-hr >8.0 mmol/L
Singleton pregnancy
First pregnancy after the index pregnancy
Pregnancy concluded by December 1995

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Illawarra area of New South Wales, Australia (predominantly Caucasian inhabitants) with a population of ~280,000, well defined and isolated. All deliveries occur in 1 of 2 hospitals in the area. All subjects were referred to an endocrinologist for the medical management of GDM and were followed over a 5-yr period, Jan, 1990 to Dec, 1994.

Design: Cohort Study

Blinding Used (if applicable): not applicable

Intervention (if applicable):

1. Hospital record/physician record review

further pregnancies
age
prepregnancy weight
height
fasting and 2-hr plasma glucose on OGTT
insulin use and dosage during pregnancy

2. Midwifes data collection form

birth weight
gestational age

3. Subjects received individualized diet during pregnancy to achieve normal weight gain, 45% to 55% carbohydrate to achieve glycemic control

all did home glucose monitoring
insulin therapy if plasma glucose> 5.5 mmol/L and/or 10% of 2-hr postprandial glucose 7.0 mmol/L or the 1-hr postprandial >8.0 mmol/L
all women received nutrition counseling by dietitian before d/c from hospital

Statistical Analysis

Unless otherwise specified, results have been expressed as a percentage or as a mean with standard deviation. Statistical tests included the t test, chi-square test, and logistic regression analysis.

Data Collection Summary:

Timing of Measurements:

Data collected through hospital record/physician record review and midwifes data collection form.

Dependent Variables:

Recurrence rate of GDM

Independent Variables:

1. Hospital record/physician record review

further pregnancies
age
prepregnancy weight
height
fasting and 2-hr plasma glucose on OGTT
insulin use and dosage during pregnancy

2. Midwifes data collection form

birth weight
gestational age

3. Subjects received individualized diet during pregnancy to achieve normal weight gain, 45% to 55% carbohydrate to achieve glycemic control

all did home glucose monitoring
insulin therapy if plasma glucose> 5.5 mmol/L and/or 10% of 2-hr postprandial glucose 7.0 mmol/L or the 1-hr postprandial >8.0 mmol/L
all women received nutrition counseling by dietitian before d/c from hospital

Control Variables:

Description of Actual Data Sample:

Initial N: There were 480 women with GDM seen over the 5-yr period, 1990-94.

Attrition (final N): Of the 480 women, 101 (21%) had completed another pregnancy. One patients did not have an OGTT and was excluded. 100 remained.

Age: mean age 29.8 +/- 5.1 years

Ethnicity: predominantly Caucasian

Other relevant demographics:

Anthropometrics:

Location: Illawarra area of New South Wales, Australia

Summary of Results:

Means + SD Index and subsequent pregnancy
	Index	Subsequent
Age, yr	29.8+5.1	31.8+4.2
Parity	1.1+1.3	2.0+1.3
BMI:	26.0+5.5	27.4+6.4
OGTT, wk	29.7+3.3	9.1+0.7
Birth wt, kg	3.4+0.6	3.5+0.7
Gestation, wk	39+1.4	38.9+1.2

100 patients remaining in the study:

35 (35%, 9% CI, 25.5-44.5) had GDM in their subsequent pregnancy.

Using logistic regression analysis, both a lower age (P=0.033) and lower parity (P=0.045) were predictive of the nonrecurrence of GDM. Women who gained weight between pregnancies were also more likely to have a recurrence of GDM.

Previous use of insulin did not appear to be a risk associated for the recurrence of GDM. Most women who used insulin in the first pregnancy did not require it in the second; those requiring insulin in the second pregnancy were on insulin for the first time.

Author Conclusion:

GDM recurrence was ~33% in this Caucasian population. Women who had a recurrence of GDM were older, more parous, and also had an increase in weight between pregnancies.

The medical management of the index pregnancy was under the care of one clinician and of the 35 with recurring GDM, the same clinician subsequently cared for all but 2.

Funding Source:

Government:	Illawarna Area Health Service (Australia),
University/Hospital:	University of Wollongong

Reviewer Comments:

This study suggests that the one risk factor—postpartum weight gain—can be modified with lifestyle changes.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	Yes
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	N/A
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes